1. Field of the Invention
The present invention relates in general to wireless servers for communicating user terminal devices wirelessly to Internet, and relates in particular to a wireless server system that can provide a seamless service to a terminal unit when the terminal unit moves from one managing district to another managing district.
2. Description of the Related Art
There has been an increasing need for mobile computing in recent years. Mobile computing performs information processing by connecting to an existing Internet service network through a mobile-phone circuit, for example. A feature of the circuit used for mobile computing is that it enables communications from mobile sites by utilizing mobile phone circuits.
However, communication devices dependent on the conventional wired communication network operate on communication protocols that are designed for fixed communication services, and present a problem that communication is terminated when a terminal unit moves to a location beyond the capability of sub-net services. Further, there are problems of excessive time of waiting to be connected to the telephone network, and if the line is congested, it may be impossible to secure a line.
It is an object of the present invention to address the above-identified and other short-comings of conventional systems and methods. A consistent object is to provide a communication system and method that can continue to communicate without using telephone circuits, even when a terminal unit moves out of a sub-net district.
The objects are achieved in a wireless server system and method, for wirelessly connecting a terminal unit having a terminal device and wireless mobile device to the Internet, including not less than one wireless server for communicating with Internet; and a plurality of wireless station devices connected to the wireless server for wireless communication with the terminal unit by way of the wireless mobile device; wherein one wireless server within a district of communication range of the wireless station devices is designated as a home server for the wireless mobile device, and the terminal device communicates with Internet by way of the wireless mobile device.
An advantage of the present server system and method is that, because one wireless server is designated as the home server for the wireless mobile device, within a managing district of the home server that can communicate with the wireless mobile devices and the home server performs the tasks of approving a terminal connection and issuing an Internet Protocol, IP, address, the mobile device is able to carry on communicating in managing districts other than the managing districts of the home server.
The objects have also been achieved in a wireless mobile device that includes a memory section for storing a last operational frequency used by the wireless mobile device and down-frequencies of a peripheral wireless station device; a read-only-memory section for storing permissible operational frequencies for sending and receiving data through the wireless mobile device; and a judging section for comparing frequencies stored in the memory section and permissible operational frequencies stored in the read-only-memory section, and judging whether or not an operational frequency to be used by the wireless mobile device is useable; wherein up-frequencies transmitted from the wireless station device are tested by using successively the last receiving frequency, the down-frequencies of the peripheral wireless station device and the permissible receiving frequencies so that a terminal registration request is transmitted only when a received up-frequency matches a receiving frequency permitted for the wireless mobile device.
An advantage of the present wireless mobile device is that it is only necessary to search among the down-frequencies of the peripheral station devices to find a useable frequency, because a down-frequency can be selected by the wireless terminal unit for sending a terminal registration request to a wireless server.